HARDWICKE'S S C lEN CE|. GOS S IP. 



43 



GEOLOGY. 



Geological Maps. — Those of our geological 

 readers who desire instruction in practical geological 

 mapping cannot do better than read an able and 

 well-written article on " How to make a Geological 

 Map," in the Popular Science Review, by Mr. H. B. 

 Woodward, P.G.S., of the Geological Survey of 

 England and Wales. 



EossiL Wood. — I have cut a few sections of coal 

 that I thought might contain structure, but with 

 the same result as E. T. Scott. If the coal is 

 interspersed with mineral charcoal, as is the case 

 with some, he may expect some little result. 

 Witham, in his "Fossil Yegetables," speaks of 

 the difficulty of finding structure in coal. He says 

 the Bovey coal does not present very decided 

 characters under the microscope, yet the figure of 

 the block from which he cut has a very ligneous 

 look. There are, at times, fragments of fossil wood 

 to be met with in coal with the woody structure 

 very well preserved by] the specimen becoming 

 calcified before bitumenization set in. It is said 

 that lignite or brown coal of the Miocene formation 

 shows structure. I am not able to speak to the 

 truth of this, having never cut sections of it. If 

 E. T. Scott will send me his address, I will send 

 him a few fragments of fossil wood from coal that 

 will repay the trouble of preparing for the micro- 

 scope. — John Butterworth, Goat's Shaw, nr. Oldham . 



Antiquity of Man in America. — The dis- 

 coveries that are constantly being made in this 

 country are proving that man existed on this conti- 

 nent as far back in geological time as on the Euro- 

 pean continent ; and it even seems that America, 

 really the old world geologically, will prove to be 

 the birthplace of the earliest race of man. One of 

 the latest discoveries is that by Mr. E. L. Berthered, 

 given in full, with a map, in the " Proceedings of 

 the Philadelphia Academy of Sciences for 1872." 

 Mr. Berthered there reports the discovery of ancient 

 fireplaces, rude stone monuments, and implement s 

 of stone in great number and variety, in several 

 places along Crow Creek in Colorado, and also in 

 several other rivers in the neighbourhood. These 

 fireplaces indicate several ancient sites of an un- 

 known race, differing entirely from the mound- 

 builders and the present Indians, while the shells 

 and other fossils found with the remains make it 

 appear certain that the deposit in which the ancient 

 sites are found is as old as the Pliocene and, per- 

 haps, as the Miocene periods. As the fossil shells 

 found with the remains of man are estuarine forms, 

 and as the sites of the ancient towns are on ex- 

 tended points of land and at the bases of ridges or 

 bluffs, Mr. Berthered thinks the localities Irave been 

 near some ancient fresh-water lake. 



A " Missing Link."— Professor Marsh has com- 

 municated a short note to the Annals and Magaziyie 

 of Natural History for January, on what he ap- 

 propriately terms "one of the most interesting of 

 recent discoveries in Paleeontology." It is the 

 skeleton of a fossil bird, recently found in the creta- 

 ceous shales of Kansas. The remains indicate an 

 aquatic bird, as large as a pigeon, and differing 

 widely from all known birds in having biconcave 

 vertebrae ! The cervical, dorsal, and caudal verte- 

 brae preserved, all show this character, the ends of 

 the centra resembling those of the fossil marine 

 reptile called Plesiosaurus. The rest of the skele- 

 ton presents no marked deviation from the ordinary- 

 type of birds. The wings were large in proportion 

 to the posterior extremities. The humerus was 

 58'6 millimetres in length, and has the radial crest 

 strongly developed. The femur is small, and has 

 the proximal end compressed transversely. The 

 tibia is slender, and MS millimetres long ; its distal 

 end is incurved as in swimming birds, but has no 

 supratendiual ridge. Professor Marsh proposes to 

 name this singular creature Ichthjornis dispar. 



NOTES AND QUERIES. 



The Compass-flower. — I beg to inform James 

 Pearson that the Compass-flower does not owe its 

 existence to the imagination of the poet's brain. 

 The botanical name of this remarkable flower is 

 Silphium laciniatum, of which there are several known 

 varieties ; but one only — S. laciniatum — appears 

 to possess the peculiar property assigned to it by 

 the poet. From the statements of numerous ob- 

 servers who have examined the plant, it appears 

 that it does undoubtedly possess this peculiarity, 

 which fact is well known to the hunters and settlers 

 who frequent the vast prairies whereon it grows. 

 It proves of great service to them when overtaken 

 by night on those trackless wastes which abound in 

 North America, far from any town or habitation of 

 man, and with no otlser resource but this one simple, 

 yet wonderful, flower of the desert to direct them 

 with safety to their destination. The cause assigned 

 for this so-called polarity by Dr. Gray is, that the 

 two surfaces of the leaf are equally susceptible to 

 light. Examined microscopically, it was found that 

 the upper and under surface proper were identical 

 in structure, with exactly the same number of 

 sfomata on each surface, while the number of stomata 

 on allied species varied considerably. The result of 

 these observations showed that the meridional posi- 

 tion taken by the leaves of this plant was due to 

 tlie influence light exerted on the two surfaces, and 

 that the greatest amount of light attained m 

 northern latitudes, equally distributed on the two 

 surfaces, would be that position in which the leaves 

 are presented, north and south.- — Henry Blake. 



The " Compass-flower." — If Mr. Pearson, who 

 asks (in S.-G., Dec, p. 281) if there is such a plant 

 as the "Compass-flower," will turn \o the American 

 Naturalist, vol. v. p. 1, he will find quite a full 

 account of the polarity of tlie Compass-plant and 

 the supposed causes of it, by Mr. Whitney, and also 

 a little critique on Mr. Longfellow's description of 

 the plant.— /\ JF. Putnam, Peabody Academy of 

 Sciences, Salem, Mass. 



